16 PROCEEDINGS OF THE ACADEMY OF 



Appendix to the "Monograph of the PHILYPNI," and description of the 



genus LEMBUS of Gunther. 



BY THEODORE GILL. 



la the Proceedings of the Academy of Natural Sciences for April, 1860, (pages 

 120 to 126,) there has been given a monograph of the Philypni, of which two 

 genera, represented by three species, were described. Some time after the 

 publication of that memoir, the first volume of the " Catalogue of the Acan- 

 thopterygian Fishes" of the British Museum, was received. Dr. Albert Gun- 

 ther, the author, among the addenda of that volume, has described a new 

 generic form founded on a species discovered by Mr. Fraser in the Andes of 

 Ecuador ; the new genus was named Lembus, and is said to be " a true repre- 

 sentative in South America of the Perches of the Arctic regions." In its 

 general appearance, it is stated to resemble Luciqperca, or some of the other 

 elongate Perches. 



A perusal of the generic and specific diagnoses of Dr. Gunther has con- 

 vinced us that there must be some error in the reference of his new form to 

 the family of Percoids. 



In the diagnosis of the genus, there is said to be no lateral line, and the first 

 dorsal has seven slender spines. 



In the specific description, the branchiostegal membrane is stated to be "fixed 

 to the isthmus, without touching that of the other side," and " the ventral is in- 

 serted exactly under the pectoral, and composed of one feeble spine and five 

 rays, the fourth of which is the longest, nearly reaching to the vent," "The 

 pseudobranchiae are absent." " The opercles are neither serrated nor armed. 



As none of these characteristics are common to the true Percoids, great 

 doubt may be entertained as to the propriety of referring a fish with such 

 features to that family. And as in all of those same characters, it resembles 

 the Gobioids, and especially theEleotroid genera, we entertain little or no doubt 

 that it is really a member of the same family. 



One of Gunther's generic characters is the presence of a " band of villiform 

 teeth on the jaws and on the vomer." There are six branchiostegals. The genus, 

 therefore, belongs to the group of Philypni.* 



The scales are described as " rather small, ctenoid, pentangular, with the 

 basal margin vertical." This form of the scales is a common feature of the 

 Gobioids with ctenoid scales, and although only the descriptive phase "ctenoid " 

 is applied, it is not to too much to infer that, like its 'allies, Lembus has the 

 scales simply pectinated on their posterior margins. The form of the body is 

 described as resembling that of Lucioperca ; Lembus is consequently on account 

 of the size and pectination of the scales, and the general form of the body, 

 more nearly allied to Philypnus as restricted by us than to Boslrichthys. The 

 true generic characters, so far as can be gathered from the description, appear 

 to be the following: 



Lembus Gunther. 

 Synonymy. 



Lembus Gunther, " Catalogue of the Acanthopterygian Fish," &c, vol. i. p. 



505, 1860. 



Head elongated, above depressed, and flat between the eyes. Mouth large, 



the supramaxillary bones extending to or beyond the vertical of the anterior 



border of the eye ; lower jaw projecting beyond the upper ; nostrils distant ; 



*The pseudobranchiae are absent, so far as yet known, only in the genera Cnidon of 

 Muller and Troschel, and Lates of Cuvier among the Percoids. The preoperculum 

 is sometimes entire in some of the Percoid genera, but the operculum has always one or 

 more spines. The Etheostomoids have the inner rays of the ventrals longer than the 

 external, but they are much more nearly related to Gobioids than to Percoids. 



[Jan. 



